Protractor



Sept. 19, 1939. w. J. ADAMS PRoTAcTon v Filed March so, 1938 2sheets-snee; 1

` INVENToR. i W/P'Z'Zazza Jaam AT roRNEY Slept. .19, 1939. w. J. ADAMSPRoTRAcToR .Filed vMarch 30, 1938 2 SheetS-Sheeb 2 INVENToR. l fafa s,

AT IoRzvlsY x Hlall 1mm! Patented sept. 19, 193e PATENT PBDTRACTOE i "1rJ. A Washington, D. C.

Appusauon Msi-eh so. 193s, sensi No. 199,006

schim.

This invention relates to improvements in protractors or like scribinginstruments.

One object of the invention is to provide a protractor which may bereadily and conveniently c used i'or scribing a circle or any part of acircle of a given diameter, marking H degree points, and inscribingstraight lines at any degree angle radial to the center and circle orany sector thereof.

Another object oi' the invention is to provide a protractor embodyingrelatively movable pivotallv connected blade and frame membersy onebearing' an arcuate degree scale and one or the other carrying aradially adjustable indicating or marking pin whereby pattern drawingsor layouts for boring, drilling or other work may be performed with easeand facility.

Still another object of the invention is to provide a protractor oi' atype suitable for the production of instruments for the use ofdraitsmen,

model and pattern makers and machinists in more readily and proiicientlycarrying out certain kinds of their work.

The invention consists of the features of cond struction, combinationand arrangement oi parts, hereinafter fully described and claimed,reference being had to the accompanying drawings, in which: Fig. l is aplan view, with parts in normal posiif tion, of a protractor of a typeem ng my invention adapted for scribing and layout marking work.

Fig. 2 is a view tractor. 5 Fig. 3 is a bottom plan view thereof.

Fig. 4 is a, view similar to Fig. 1 showing adjusted positions of theblade and marking pin for a certain kind oi'` work.

Fig. 5 is a section on the line 5 5 oi' Fig. 1. D Fig. 6 is a section onthe line 6-6 of Fig. 5. O Fig. 'l is a similar section through the bladeand marking pin, taken at right angles to that shown in Fig. 5 andillustrating a marking action. Fig. 8 is a. section on line 8-8 ofFig. 1. i Fig. 9 is a view of the bearing bushing of the Apivot pinremoved.

Fig. 10 is a view of one of the pins, for example the pivot pin.

Fig. 11 is a view of a templet or work-plate or panel showing one kindof layout work for which the protractor is adapted.

Fig. 12 is a View oi the marking pin pointer. Fig. 13 is a view of aform of they protractor embodying the invention.

Referring non/more particularly to Figs. l te l0,

in side elevation oi the procircumference of the inclusive, and 12 ofthe drawings, I provide a protractor comprising a frame member I and ablade member 2. The frame member I comprises an arcuately curved bodyportion 3 having at one end an inwardly extending arm 4 and at the op- 5posite end an outwardly extending arm 5. the arm 4 being provided at itsfree end with an aper tured portion or bearing eye 6 and the arm 5 beingof some material width to serve as a steady rest on which a portion ofa. hand oi' the operator 10 may bear to hold the tool in position forscribing or other operations.

lThe blade member 2 comprises a substantially semi-circular plate havinga. curved edge l extending substantially through an arc of 180 and l5having an opposite straight edge divided on the opposite side of itscenter into two portions 8 and 3 respectively.' The 'curved edge of theblade at one side underlies an overhanging ange or part of the bodyportion 3 so as to be guided thereby in 20 its movements, and the upperface of the blade or plate is provided with scale graduationsextending'along its curved edge at 10 intervals and divisions'thereoi.'as shown.

The straight edge portion 8 of the blade extends 25 radially of thecircle of which the edge l' forms an arc in line with one of theterminal degree graduations oi' the scale. The edge 9 at the oppositeside of the center oi the blade is, however, onset rearwardly beyond,but lies substantially parallel with, the line 9.

At the pointof intersection of the edges 8 and 9. the blade is formedwith an opening i0 having an overhanging flange I I. This openingreceives the lower end of a bushing l2 having a tubular or 35 sleeveportion I3 projecting upwardly therefrom, the upper portion of whichbushing and which sleeve portion are provided with external screwthreads. Engaging the threaded portions of this bushing and sleeve is anexternally threaded 40 tubular casing I4 bearing at its lower endagainst a washer I5 `disposed between the same and the eye 6 of theframe member 3,l whereby the bushing I2 and casing Il are secured inposition and a Y pivotal connection between the eye B and bushing v I2afforded on which the plate 2 may have swinging motion relative to theframe member I so that the degree point thereof may aline with anindicating edge I6 of the frame member lying in dia- 'metric alinementwith the pivotI point of the blade. 60 The bushing I2 is bored toreceive a setting pin It having a lower conical or pointed end portionIB, and which extends upwardly through the sleeve I3 and is providedwith an abutmentilange or shoulder I9. Encircling the upper portion ofd5 this pin is a coiled pressure or backing spring 25 bearing at itslower end on the flange or shoulder I3 which limits the extreme downwardmovement of the pin I1. The upper end of the casing Il is provided witha milled enlargement 2 I forming a linger grip portion by which saidcasing member may be rotated in applying and removing it, andiltted inthe upper end of this casing member is an adjusting sleeve 22 whichreceives the upper end of the spring 2II and is provided with a milledhead portion 23 which bears thereon and by means of which the upperportion of the casing is closed and the pressure of the spring i on thepin I1 adjusted to regulateI its resistance to recession when bearing ona piece of work. The pointed end of the pin is designed to be tted orforced into a recess 2l formed in a piece of work 25 to set or centerthe device :at the pivot point for use, such pin and bearing exerted onthe arm 5 being employed to hold the protractor steadfast in workingposition. The oset edge portion 9 of the blade 2 advantageouslyincreases the area of said blade in the region of its pivot point in anIobvious manner and increases its area of engagement with the bodyportion 3 of the frame member I so as to be better guided thereby.

Formed in the blade or plate 2 is a guide slot 25,which opens throughthe topl and bottom of the blade. This slot terminates at one endadjacent to and in alinement with the pivot point of the blade andextends therefrom radially toward the curved edge of the blade with itsoppo-f site end terminating adjacent to the 90 graduation. 'I'he base ofthis opening intersects a 35' guide groove 21 having straight parallelwalls and which is formed in the underside of the blade and extends thefull distance between its edges 1 and 9. This groove also intersectstheopening I0 and receives a retaining flange 28 on the bushing I2 whichunderlies the flange I I, whereby said bushing is held from upwarddisplacement, and opposite edges of this ilange 28 may be made straightand parallel with the straightwalls of the groove 21 to hold the bushingI2 from axial rotation. l

Fitted to slide in the slot 26, .which is narrower than the groove 21,whereby a flange 23 overhanging said groove is provided, is a bushing 30which is bored for the passage of a marking pin or punch 3I. Thisbushing is externally of noncircular form, having'two attened sides andtwo curved sides, the curved sides thereof being provided with screwthreads to engage internal screw threads on a tubular casing 32, whichis thus connected with the bushing to slide therewith longitudinally ofthe slot 25. The bushing is provided at its base with a flange 33underlying the flange 29, whereby the bushing is held from upwarddisplacement, and two of the opposite sides of this flange are madestraight-surfaced for sliding engagement with the walls of the groove 21and to hold the bushing from axial rotation. The pin 3l extends upwardlywithin the casing 32 and outwardly through a threaded adjusting sleeve34 fitted inthe upper end of the casing, which sleeve is provided with amilled gripping'flange or enlargement 35. At a .point above the bushingthe pin 3l is provided with an annular flange or shoulder 35 and betweenthis ange or shoulder and the bushing is interposed a coiled spring 31which encircles the sleeve and exerts its expan- 'sive force on the angeto hold the marking pin normally elevated to a non-working position. Bythe blow of a hammer 38 or yother tool delivered upon the upper end ofthe pin 3 I the lower pointed end 39 thereof may be forced downward toform a marking or indicating depression 40 inthe surface of the work 25.Extending parallel with and at one side of the slot 26 on the upper faceof the plate 2 is a scale 4I indicating degrees of adjustment of themarking pin radially of the blade between its pivot and curved edge, sothat indi- 'cating marks or depressions '40 may be formed in .a piece ofwork at any distance radially of the blade from the setting pin I1 andin a circle or arc of any radius concentric with said pin as a center.Carried by the setting pin for cooperation with the scale 4I `is apointer I2 which is held between the plate 2 and base of the casing 32,-the bodyof said pin, as shown in Fig. 12, having an angular openingtherein conforming to the shape of the bushing 30 whereby the pointer ismounted to slide with the bushing and pin, but is held from axialrotation...

The construction of the protractor above described adapts it for4 manyand various uses in drafting work and in inscribing or marking of!asurface for the production of templets or patterns or for marking andpreparing points extending in a circle or on an arc-of greater orless'radius and-number of degrees forboring or other operations.Obviously the blade 2 may be adjusted on its pivotal connectionatdiiferent angles with relation to the edge I6, as shown in Figs. 1 and4, for the use of its curved edge in inscribinga circle of a fixeddiameter of arcs of any degree of that circle, while the edge 8 may beused in inscribing straight `lines at any point about and radially tothe setting pin I1 and at an angle to the line described along theedge 1. As stated, the marking pin 3| may be employed for marking oiIportions of a piece of work for boring or other operations. l

Fig. 11 shows a use for which it is adapted, for example, -for makingmarks or indentations 40 in a radio panel 43 at spaced points in an arcconcentric with a depression or recess 24 receiving the setting pin, themarks 40 indicating points at which,` the panel is to.be bored ordrilled to receive switch contacts or the like. Similarly, theprotractor may be used for various and sundry kinds of scriblng ormarking work in forming templets, patterns and indicating boring ordrilling points in all kinds of material.

Fig. 13 shows .a modified form of the device 'which may be used in asimilar manner to the device shown in Figs. 1 to 10, inclusive, butwhich provides a suitable form of device adapted particularly fordrafting work, in which I' is a frame member embodying a protractorscale Ia having a scribing edge 1 and the ends of which are connected bya base or cross piece Ib to which a swinging blade member 2' isconnected by a pivot andv setting pin I1. The blade is formed with aguide slot 25' and with scale indications 4I and in said slot slides amarking pin or indicator 3 I having pointers l2' for cooperation withsaid scale indications and which may be similar in construction andmounting to the marking pin 3|. a pointer I5' for cooperation with the180 scale and at certain points on the 180 scale the frame member isprovided with notches 44 for convenience of the draftsman in marking offscale points on the work. 'Ihe many uses for which this modified form ofthe device is adapted will be readily understood from the foregoingdescription and will be apparent to model, tool and pattern makers,draftsmen and other like artisans.

VAFrom the foregoing description, taken in con- At its free end theblade 2' is provided with :,ivasas nection with the drawings. theconstruction, mode of use and advantages of my improvedprotractor willbe readily understood and appreciated by those versed in the art withoutal further and extended description. While the structures disclosed arepreferred, it will, of course. be understood that changes in the form,construction and arrangement of parts within the scope of the appendedclaims may be made, without departing from the spirit or sacriiicing anyof the advantages of the invention.

What I claim is:

1. A protractor comprising relatively movable pivotally connected i'rameand blade members, said blade member having a curved edge extending onthe arc of a circle concentric with said pivotal connection and beingprovidedy with degree graduations extending` along said edge, one ofsaid members being provided with an elongated slot extending radially inany relative position of said frame and blade membersl between saidpivot point and the curved edge of the blade member, and a markingdevice adjustable along said slot and 'comprising a casing, a markingpin ing end adapted to be projected downward through the slot and anupper end portion prof jecting above the casing and adapted lto be en-vgaged by suitable means to force the pin down- Ward, a spring fornormally holding the pin retracted, and means for regulating the tensionof said spring.

2. A protractor frame and blade members, being substantially ofsemi-circular formV and having an arcuate scribing edge and providedalong said edge with scale graduations, said members being pivotallyconnected at a point equidistant from and concentric withsaid edge, oneof said members being provided with an elongated slot extending radiallyin any relative pov sition of said frame and blade members between saidpivot point and the curved edge of the blade member, and a markingdevice adjustable along said slot and comprising a casing, a marking pinvertically movable in said casing, said pin having a lower marking endportion, an upper end portion projecting above the casing and adapted tobe engaged by suitable means to force the pin downward, and a shoulderdisposed at an' intermediate point thereon within the casing, a springacting on said shoulder to hold the pin normally retracted, and meansengageable with the casing for engagement with said shoulder to limitthe upward movement of the pin and to adjust the working position of thepin and regulate the tension of the spring.

3. A protractor comprising relatively movable frame and blade members,one of said members being substantially of semi-circular form and havingan arcuate scribing edge and provided along said edge with scalegraduations, said members being pivotally connected at a pointequidistant from and concentric with said edge, one of said membersbeing provided with an elongated slot extending radially in any relativeposition of said frame and blade'members between said one of saidmembers pivot point and the curved edge of the blade member, and amarking device adjustable along said slot and comprising a bushing inslidable engagement at its lower end with the slotted member, a casinginto which said bushing extends, a marking pin projecting at its lowerend downwardly vthrough the bushing and at its upper end above thecasing, said pin being provided vertically movable in said casing andhaving a lower markcomprising relatively movable A said curved bodybushing and pin normaliy a springdis-f members being pivotally connectedat a point equidistant from and concentric with said edge, a springretracted marking pin and punch carried by and movable with one of saidmembers and slidably adjilistablev radially in any relative angularposition of said blade and frame members between said pivot point andthe curved edge of the blade member, and means-for adjusting saidmarking pin to regulate its extent of projection and simultaneouslyregulating the tension of the spring.

5. A protractor comprising a frame member, a blade member comprising aplate having an arcuate scribing edge bearing scale graduatlons and astraight edge, the latter having a portion at one side of its centerextending radially with respect to one end of said arcuate scribing edgeand a portion at the opposite side of its center offset l rearwardly ofthe line of the rst-named portion, a setting pin pivotallyconnectlng,the frame and blade members at the point of intersection of.said portions of 'the straight edge and concentric with the curved edgeof the blade, said blade being provided with a 'slot extending radiallybetween its curved edge and said pivot point, and a marking plungeradjustable along said slot.

6. A protractor comprisinga frame member, a blade member comprising aplate having a curved vside of its center offset rearwardly of the lineof the first-named portion, a setting pin pivotally connecting the frameand blade members at the point'of intersection of said/portions ofI thestraight edge and concentric with the curved edge of the blade. saidblade beingprovided with a slot extending radially i along said slot,and means for regulating the action of the retracting spring.

7. A protractor comprising a blade member in the form `or a, platehaving an arcuately curved edge at one side thereof and provided along"said edge withscale graduations, and a frame member embodying a bodyportion curved to conform and movable along said c urved edge of theplate and angularly arranged arms at opposite ends of portion of theframe member, one projecting outwardly beyond the curved body portion'of the frame member and curved edge of the plate and having a scrbingedge and the other projecting inwardly from said body portion andradially with respect to the curved edge of the plate and pivoted at itsinner end to the edge of the plate opposite thecurved edge at a pointconcentric with said curved edge. 8. A protractor comprising relativelymovable pivotally connected frame and blade members,

said blade member having a curved edge extendalong said slot a sleeveadjustably mount l at. .ing on the arc of a. circle concentric with saidthe upper end of the casing, a marking pin expivotal connection andbeing provided with detending through the casing and sleeve and havinggree graduations extending along said edge, one an upper -striker endprojecting above the sleeve of said members being provided with anelongated and a. lower pointed marking end disposed for slotextending'radially in any relative position downward movement throughsaid slot, and a. of said frame and blade members between said springdisposed between the pin and sleeve for pivot point and the curved edgeof the blade normally holding thepin retracted.

member, and a marking device embodying a cas- 10 ing siidably mounted atits lower end for travel lWILLIA M J. ADAMS. 1

